Electromagnet for magnetizable members

ABSTRACT

An electromagnet for removing and replacing magnetizable lids with means being provided for minimizing the tendency for lateral movement between the electromagnet and the lid including bands having teeth thereon disposed about the periphery of the electromagnet with the teeth projecting from the working face and adapted to directly engage the lid whether warped into a concave or convex configuration.

nited States Patent fivvairs Jan. 18, 1972 [54] ELECTROMAGNET FOR 3,116,571 1/1964 Riggan et a1 ..279/1 M MAGNETIZABLE MEMBERS 3,440,145 4/1969 Tucker et a1 ..294/65.5 X

[72] Inventor: Ralph W. Edwards, 13245 Gremoor FOREIGN PATENTS OR APPLICATIONS Elm Gmve 53122 410,634 3 1925 Germany ..294/65.5 [22] Fil d; O t, 29, 1969 147,593 6/1921 Great Britain ..335/291 pp 872,125 Primary Examiner-Even C. Blunk Assistant Examiner-W. Scott Carson [52] U 5 Cl 294/65 5 269/8 Att0rney--Hofgren,Wegner, Allen, Stellman& McCord [51] Int. Cl. ..lB66c1/06 [58] Field of Search... ..294/65.5; 269/8, 276; 279/1 M; [57] ABSTRACT 214/114; 335/286, 291 An electromagnet for removing and replacing magnetizable lids with means being provided for minimizing the tendency [56] References Cited for lateral movement between the electromagnet and the lid including bands having teeth thereon disposed about the UNITED STATES PATENTS periphery of the electromagnet with the teeth projecting from the working face and adapted to directly engage the lid 1,141,412 6/1915 Pool ..294/65.5 X whether warped into a concave or convex configuration 2,117,132 5/1938 Baermann ...294/65.5 X 2,993,395 7/1961 Bohn ..269/8 3 Claims, 4 Drawing Figures 1 ELECTROMAGNET FOR MAGNETIZABLE MEMBERS BACKGROUND OF THE PRESENT INVENTION This invention relates to electromagnetic handling devices and more particularly to an electromagnet for removal and replacement of the cover plates in the tops of chambers and the like.

The electromagnetic-handling device has use in the coke oven field and in particular one'type of coke oven battery includes a plurality of separate coking chambers which are charged with coal through charging holes in the top of the chambers. There are generally provided several charging holes associated with each chamber. For the purpose of supplying coal to the chambers a larry car is conventionally provided that rides on suitable guideways over the top of the oven to the individual coking chambers. There have been provided in the past devices which are intended to remove the charging hole covers mounted adjacent the lorry car and in some cases carried by the larry car itself.

One prior charging hole cover handling device includes a remotely operable electromagnetic device that is controlled from a remote location. An electromagnet is provided that has a working face that moves vertically down into engagement with the charging hole cover or lid, lifts the cover or lid vertically upward and thereafter moves the lid away from the charging hole permitting the open hole to be charged with coal. Thereafter, the electromagnet mechanism moves the lid back into position aligned with the hole and then lowers the lid into its seated position within the hole. The electromagnet then releases the lid.

During the lid replacing operation, in order to securely seat the lid within the charging hole, electromagnetic devices provided in the past have oscillated the oven lids laterally to as sure proper seating within the lid seats in the charging holes. One of the problems encountered in pivoting or oscillating of the oven lid is that because of the high temperatures encountered in coke ovens of this type the lids frequently become warped so that the electromagnetic surface does not make contact over the entire working face of the electromagnet. The result of this is that frequently the electromagnetic field will be unevenly distributed over the oven lid to the extent that the electromagnet does not have sufficient force to oscillate the lid as required during manipulation.

It is a primary object of the present invention to provide an electromagnet for handling coke oven lids that minimizes the tendency for the lid to move laterally with respect to the magnet as a result of lid surface distortion.

SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, an electromagnet is provided for removing and replacing the lids of coke ovens that minimizes the tendency for lateral movement between the lid and the electromagnet during oscillation or rotation of the lid by the magnet through the provision of two metal bands fixed about the periphery of the electromagnet and having teeth projecting from the working face of the electromagnet and engageable with the oven lid. The bands are similar to conventional band saw blades and have rake angles corresponding similarly thereto. The teeth of the two blades are pointed in opposite directions to provide greater assistance to rotation of the lids in either direction of movement thereof. The electromagnetic field is concentrated through the teeth of the saw blade to create a plurality of gripping points which prevent lateral movement of the lid relative to the teeth.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of the present electromagnet shown holding an oven lid over the top of a coke oven;

FIG. 2 is an enlarged elevation of the electromagnet by itself;

FIG. 3 is an enlarged fragmentary elevation of a portion of the electromagnet illustrating the holding bands; and

FIG. 4 is a fragmentary view of the holding hands taken generally along line 4-4 of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly to FIG. 1, an electromagnetic assembly 10 is shown which is adapted to remove and replace a cylindrical cover plate or lid 12 from a charging hole 14 in top 16 of a horizontal coke oven battery.

The electromagnetic device 10 includes a mechanism for raising and lowering electromagnet l8, shifting it laterally and for oscillating it about the axis 19 of the electromagnet.

As noted above, it is desirable to rotate or oscillate the electromagnet 18 either for the purpose of moving cover lid 12 away from the charging hole 14 or for the purpose of securely seating the lid in seat 21 in charging hole 14, and the electromagnetic assembly 10 includes provision for rotating or oscillating magnet 18 for this purpose.

As shown in FIGS. 2, 3 and 4, the electromagnet 18 includes a generally cylindrical portion 23 with an enlarged annular flange 24 and a flat planar working face 25. Suitable coils are provided within the electromagnetic member 23 which are supplied current through lead fittings illustrated at 27 in FIG. 2. Threaded members 30 project upwardly from the electromagnet 18 to secure it to the electromagnetic device 10.

For the purpose of spacing the working face 25 from the surface 33 of lid 12 and for the purpose of minimizing lateral movement between the cover 12 and electromagnet 18 steel bands 35 and 36 are provided.

The bands 35 and 36 are similar in construction to conventional band saw blades having teeth 37 and 39 respectively in direct contact with the upper surface 33 of lid 12.

The teeth 39 on band 36 face in one direction while teeth 37 on band 35 face in the opposite direction to provide greater holding action for the electromagnetic device.

Each of the bands 35 and 36 extend almost entirely about the annular periphery of the electromagnet 18 within recess 41, shown in FIG. 3. As shown in FIG. 2 ends 43 of band 36 are spaced approximately one-eighth inch apart to allow for temperature distortion. The ends of the band 35 are similarly spaced one-eighth inch apart but at the opposite side of the electromagnet 18 and recess 41 so that a full 360 of teeth are provided.

In one exemplary construction the bands 35 and 36 were hard edge, flexible back band saw blades having eight teeth per inch, 1 inch in width and 0.035 inch in thickness.

For the purpose of securing the bands 35 and 36 in position an annular clamping ring 47 is provided and is seated within the recess 41 and directly engages the outer surface of band 36.

To hold the clamping ring 47 in position, a plurality of setscrews 48 are provided about the periphery of the clamping ring which pass through apertures 50 in bands 35 and 36 and into recesses 52 in the electromagnet body 23. The saw blades make contact with the lid in areas where the warp of the lid would otherwise prevent contact. The saw blades assure that contact is made and that torque is produced.

In practice, the saw blades act as magnetic lines of flux concentrators so that the holding force is concentrated in and through the blade points. With the saw blade points in contact, there are high concentrations of holding force at each point and even at those points that are spaced. from the lid due to the warp of the lid certain holding forces will pass through the airgap and provide some holding force between the magnet and the lid. The multiplicity of points of contact and flux concentrations will provide the magnet with a multiplicity of gripping areas to be utilized to transmit oscillatory and turning forces from the magnet to the lid.

In prior devices, electromagnets with a holding force of 6,200 pounds could not hold a 70 pound lid for turning an oscillatory motion when the lid had an appreciable warp. Now no dropping or sliding problems exist in providing violent or sensitive oscillations and gyrations to the lid from the magnet.

I claim:

1. An electromagnetic oven lid remover, comprising: a generally cylindrical electromagnet having a working face,

, meansfor supplying current to said electromagnet to produce first side of the electromagnet, a second band having-metal teeth thereon contiguous with said first band and having ends spaced apart at the other side of the electromagnet, the teeth on said bands facing in opposite directions, said teeth projecting beyond said working face, and a circular clamp around said bands for fixing the same to the electromagnet.

2. An electromagnetic lifting assembly for a magnetizable member comprising: a generally cylindrical electromagnet having a working surface, means for supplying current to said electromagnet to produce a magnetic field adjacent said surface, means for minimizing relative movement between the electromagnet and the magnetizable member including, a first band having metal teeth thereon surrounding said electromagnet, and a second band having metal teeth thereon contiguous with said first band, said teeth on said bands facing in opposite directions, and said teeth projecting beyond said working surface, and serving as flux concentrators for said working surface.

3. An electromagnetic magnetizable lid mover, comprising: an electromagnetic member having a generally flat working surface, means for supplying current to said electromagnetic member to provide a magnetic field adjacent said working surface, and means for minimizing lateral and rotational movement between the working surface and the oven lid, said means comprising projection means extending from said electromagnetic member and engageable with said lid, said projec tion means including a first metal band having a plurality of rigid teeth extending therefrom, said band being fixed in a generally circular position surrounding said working surface and said teeth of said band having a rake angle in a first direction, and a second metal band having a plurality of rigid teeth extending therefrom and being mounted adjacent said first band, said teeth on said second band having a rake angle in a direction opposite to the rake angle of the teeth on said first band. 

1. An electromagnetic oven lid remover, comprising: a generally cylindrical electromagnet having a working face, means for supplying current to said electromagnet to produce a magnetic field adjacent said face, means for minimizing movement between the electromagnet and the oven lid including, a first band having metal teeth thereon surrounding said electromagnet, said first band having ends spaced apart at a first side of the electromagnet, a second band having metal teeth thereon contiguous with said first band and having ends spaced apart at the other side of the electromagnet, the teeth on said bands facing in opposite directions, said teeth projecting beyond said working face, and a circular clamp around said bands for fixing the same to the electromagnet.
 2. An electromagnetic lifting assembly for a magnetizable member comprising: a generally cylindrical electromagnet having a working surface, means for supplying current to said electromagnet to produce a magnetic field adjacent said surface, means for minimizing relative movement between the electromagnet and the magnetizable member including, a first band having metal teeth thereon surrounding said electromagnet, and a second band having metal teeth thereon contiguous with said first band, said teeth on said bands facing in opposite directions, and said teeth projecting beyond said working surface, and serving as flux concentrators for said working surface.
 3. An electromagnetic magnetizable lid mover, comprising: an electromagnetic member having a generally flat working surface, means for supplying current to said electromagnetic member to provide a magnetic field adjacent said working surface, and means for minimizing lateral and rotational movement between the working surface and the oven lid, said means comprising projection means extending from said electromagnetic member and engageable with said lid, said projection means including a first metal band having a plurality of rigid teeth extending therefrom, said band being fixed in a generally circular position surrounding said working surface and said teeth of said band having a rake angle in a first direction, and a second metal band having a plurality of rigid teeth extending therefrom and being mounted adjacent said first band, said teeth on said second band having a rake angle in a direction opposite to the rake angle of the teeth on said first band. 